Hybrid SnBi/SAC Low-Temperature Solder Bump

Albert T. Wu, Jui Lin Chao, Yu Yuan Lai, Chang Meng Wang

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


Assembling advanced electronic packaging at low temperature attracts attentions from the industry. One of the advantages is to reduce the warpage of dies and enhance long-term reliability of the chips. Although eutectic SnBi is considered a widely accepted low-temperature solder, Bi segregation after annealing drastically degrades the mechanical strength. In this study, two layers of materials, a pre-solder (Sn-0.3Ag-0.7 Cu, SAC0307) and a low temperature solder (Sn-56Bi-1Ag-0.2Cu, SB102) was reflowed sequentially to create a hybrid solder joint. The reflow temperatures were set as 170 and 190 oC, which are much lower than that of the SAC solder. Adding SAC0307 reduces the Bi content in the joint and lessens the formation of Bi-rich phase. Comparing with SB 102 joint, the hybrid bond shows increasing joint strength after aging. The facture surface indicates that hybrid joint exhibits ductile fracture mode while SB 102 joint shows brittle mode. The results prove that SAC0307/SB102 hybrid solder joint can be a promising candidate for low-temperature application for advanced electronic packaging.

Original languageEnglish
Title of host publication2023 International Conference on Electronics Packaging, ICEP 2023
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages2
ISBN (Electronic)9784991191152
StatePublished - 2023
Event22nd International Conference on Electronics Packaging, ICEP 2023 - Kumamoto, Japan
Duration: 19 Apr 202322 Apr 2023

Publication series

Name2023 International Conference on Electronics Packaging, ICEP 2023


Conference22nd International Conference on Electronics Packaging, ICEP 2023


  • SAC
  • SnBi
  • low-temperature solder
  • mechanical strength


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